User interfaces (UIs) can provide users or clients of a computer or software system with the ability to provide input to the system, thus allowing users to manipulate the system. UIs can also provide users or clients with information defining or associated with the output of the computer or software system, sometimes in response to input provided by the users within the same or a related UI. Typically, UIs consist of elements including entry fields, push buttons, tables, tabs, and other UI components. The layout of the elements within a particular UI, their operations and associated backend operations, and their connections to one or more other elements within the UI may be defined by metadata, models, and other information. The metadata, models, and other information associated with the UI and its UI components can be used by an application or web page to render and generate the UI appropriately, as well as to receive and output data and other information, as appropriate, for the actions occurring within or associated with the UI.